﻿#define _CRT_SECURE_NO_WARNINGS 1


#include <iostream>
#include <vector>
#include <string>
#include <algorithm>
#include <unordered_map>

using namespace std;

class Solution
{
public:
    string reorganizeString(string s)
    {
        int hash[26] = { 0 };
        char maxChar = ' ';
        int maxCount = 0;
        for (auto ch : s)
        {
            if (maxCount < ++hash[ch - 'a'])
            {
                maxChar = ch;
                maxCount = hash[ch - 'a'];
            }
        }

        // 先判断⼀下
        int n = s.size();
        if (maxCount > (n + 1) / 2) return "";
        string ret(n, ' ');
        int index = 0;

        // 先处理出现次数最多的那个字符
        for (int i = 0; i < maxCount; i++)
        {
            ret[index] = maxChar;
            index += 2;
        }

        hash[maxChar - 'a'] = 0;
        for (int i = 0; i < 26; i++)
        {
            for (int j = 0; j < hash[i]; j++)
            {
                if (index >= n) index = 1;
                ret[index] = 'a' + i;
                index += 2;
            }
        }
        return ret;
    }
};


int main()
{
    string s = "aab";

    string rs = Solution().reorganizeString(s);

    cout << rs << endl;

    return 0;
}


